Studies on the Question of Chemoautotrophy in Chilomonas paramecium

Publisher Website
Google Scholar
Abstract
Mass cultures of C. paramecium have been carried through more than 25 serial transfers on apparently inorganic media in glass-covered flasks under increased CO2 tension and seem capable of indefinite transfer in these solns. Maximum populations are low and variable, being greatly increased by the use of cotton plugs in place of glass covers. In none of the cultures was there significant increase in nitrite or nitrate during growth, although calculations indicate that even with the low populations, significant amts. should be formed if Chilomonas oxidizes ammonia to either of these products. Supplementing the media with vitamins, Fe++, trace elements or nitrite did not increase the max. population. Growth rates, during the logarithmic phase, are identical in inorganic and acetate media, but growth ceases much earlier in inorganic media. With small amts. of acetate, the max. population is detd. by the amt. of acetate present at inoculation. Carbon analyses of the inorganic salts and of the chilomonads showed that the salts contribute more than enough organic material to account for the chilomonad carbon present at max. population levels. No definite evidence of chemo-autotrophy could be obtained and it is concluded that previous reports of chemoautotrophy in this flagellate were based upon inadequate exptl. methods.

This publication has 3 references indexed in Scilit: